It is well-recognized that a high salt diet contributes to the hypertension of hypertension of a significant number of individuals, particularly in the African-American (AA) population. What is not well-recognized is that mental stress can be a contributing factor to the sodium load in a significant percentage of the AAs. Our research indicates environmental stress has a greater impact than previously recognized on the sodium load and corresponding blood pressure load for African-Americans who increase reabsorption {i.e. retain) sodium during mental stress. Findings from our recently completed study in adults suggests that repeated episodes of mental stress throughout the day can increase the salt intake in these individuals by as much as a third over and above their already high salt diet. This study also showed the effect of stress on sodium retention and consequent increases in blood pressure could be mitigated by treatment with an angiotensin receptor antagonist. The proposed application will examine two additional pathways through which alone or in concert with angiotensin II promote sodium retention during mental stress in these individuals. The proposed studies will for the first time in this population: a) determine if this response is due to an increase in renal sympathetic nerve activity; b) determine if activation of the immune system contributes to the response pattern; and c), translate our previous findings on the effectiveness of an angiotensin II antagonist for an angiotensin 11-induced salt sensitive patient population into clinical practice. Synergy: Projects 1 and 2 will work in concert to better understand the role of the immune system in the development of stress-related hypertension. Projects 1 and 3 will continue their joint efforts to identify the mechanisms through which adiposity leads to impaired sodium handling, particularly during mental stress. Project 1 will also utilize all three cores for purposes of subject recruitment and testing {Core A), assays {Core B), and data analyses (Core C).